Answer:
The government department responsible for environmental matters is the Environmental Protection Agency (EPA). The EPA's mission is to protect human health and the environment. They work to ensure that Americans have clean air, land, and water; prevent pollution; and conserve natural resources.
As for tourism matters, there is no specific government department in the United States that is responsible for tourism. However, the U.S. Travel Association is a national non-profit organization that represents all components of the travel industry. They work to promote and facilitate travel to and within the United States.